Information about Potassium-40:


Wikipedia	Neutron Cross Sections	X-Ray Transitions	X-Ray Attenuation

Mass-Energy Data:

Atomic Mass:	39.963999	±	0.000000	amu
Excess Mass (Δ):	-33.535016	±	0.000271	MeV
Binding Energy:	341.523214	±	0.000276	MeV
β^- Decay Energy:	1.311093	±	0.000118	MeV

"The 1995 update to the atomic mass evaluation" by G.Audi and A.H.Wapstra, Nuclear Physics A595 vol. 4 p.409-480, December 25, 1995.

Radioactive Decay Data:

Atomic Percent Abundance: 0.0117%
Spin: 4-
Half life: 1.277E+9 years ( 4.02766×10⁺¹⁶ sec., λ = 1.72097×10^-17 s^-1)
Mode of decay:
β^-
to
40
20
Ca
(Q = 1.311 MeV) Branch ratio: 89.28 %
Mode of decay:
E.C.
to
40
18
Ar
(Q = 1.505 MeV) Branch ratio: 10.72 %

R.R.Kinsey, et al.,The NUDAT/PCNUDAT Program for Nuclear Data,paper submitted to the 9 th International Symposium of Capture-Gamma_raySpectroscopy and Related Topics, Budapest, Hungary, Octover 1996.Data extracted from NUDAT database (Jan. 14/1999)

Magnetic Dipole Moments and Electric Quadrupole Moments
Ex(kev)	T_1/2	Spin	m(nm)	Q(b)	Ref. Std.	Method	Reference
0	1.28 x 109 y	4-	-1.298100(3)		[2H]	N	ZNat 29a 1754 (74)
			-1.2982(4)			AB/D	PR 86 73 (52)
				-0.061(5) st	[39K]	"Q, OL"	PR B6 757 (72)/PR A3 837 (71)

30	4.30 ns	3-	-1.29(9)		[19F 197]	TDPAD	PL 49B 261 (74)
2543	1 ns	7+	+4.1(7)			IPAD/IMPAD	NP A264 151 (76)
			+4.4(11)		[41K 1294]	RIGV	ZP A301 243 (81)

N. J. Stone, Table of Nuclear Magnetic Dipole and Electric Quadrupole Moments, to be published. 2000 Courtesy of T. Burrows at BNL/NNDC.